AWS Config - AWS Lambda Custom Rule example (YAML)

template.yml

AWSTemplateFormatVersion: '2010-09-09'
Transform: 'AWS::Serverless-2016-10-31'
Resources:
  MyFunction:
    Type: 'AWS::Serverless::Function'
    Properties:
      Handler: index.handler
      # ... 
      # all the other properties here
      # ... 
  MyCustomRule: 
    Type: AWS::Config::ConfigRule
    Properties: 
      ConfigRuleName: MyCustomRule
      Scope: 
        ComplianceResourceTypes: 
          - AWS::EC2::Instance  # listen to all instances
      InputParameters:
        desiredInstanceType: t2.small
      Source: 
        Owner: CUSTOM_LAMBDA
        SourceIdentifier: !GetAtt MyFunction.Arn
        SourceDetails: 
          - 
            EventSource: aws.config
            MessageType: ConfigurationItemChangeNotification